Investigation of thermal, crystal and magnetic behavior of addition of Nd rare earth element effect on CuAlMn shape memory alloy

Abstract

In this study, CuAlMn alloys, a popular Cu-based shape memory alloy, were chosen because they exhibit superior shape memory properties and improved ductility compared to other Cu-based SMAs. The rare earth element Nd (neodymium) was added to CuAlMn alloy at the specified atomic percentages in the composition Cu_70-xAl₂₄Mn₆Nd_x(x = 0,2,4,8) and their thermal behavior, crystal structure, surface morphology and magnetic properties were investigated after fabrication. As a result of the thermal analysis measurements, it was observed that for low Nd ratios, the austenite phase transformation initial temperature of the CuAlMn alloy was increased, while at high Nd ratios, a decrease in the shape memory property was detected. Martensitic phase and precipitate phase α phase were observed in the crystal structure properties of CuAlMn alloys without and with Nd doping. These results were also detected in surface morphology observations. In addition, the crystal size decreased from 135 to 105 nm with Nd doping. As a result of magnetic measurements, CuAlMn ternary shape memory alloy was found to be paramagnetic at room temperature. Magnetic susceptibility values of the alloys showing paramagnetic magnetic properties were calculated as 11.5 × 10^–6, 12.5 × 10^–6, 9.15 × 10^–6 and 6.15 × 10^–6 emu.Oe⁻¹.g⁻¹, respectively. According to these results, the magnetic susceptibility value decreased with increasing Nd ratio.